Looks great! I'm not sure if ill be following your way of stacking horizontal pieces or carving actual stones. I've watched just about every YouTube video on the subject for inspiration. I was wondering how you allowed for the filter and heater? I've seen people carve out a slot in the back but it really doesn't seem as tho either would function properly. Also yours seems to be large and in one piece. I'm making one for a 75 but ill have to have it cut into two or three pieces to fit it in because of my top brace. Do u have a rimless aquarium?

Kimmysparks, If you'll look back at post #8, you can see where my background is split into 2 pieces. It is still in 2 pieces, I just stacked them for the texture painting and for the pictures I took. It still comes apart into 2 pieces to make it be able to install past my center brace.

If you'll look at the background up at the top, you'll notice 4 cutouts that are part of the rock. These will allow my Intake and Return to be in front of the background and still function, while at the same time being recessed and not sticking out too far in front of the rock.

Silicone is what I'm planning on using but I'm not overly impressed with how well it holds two pieces of styrofoam together. I was wondering Sigpi906's intention. I went back and drilled 1" shafts in mine that I plan on filling with sand to help hold it down.

I'm with you on not being impressed with how well the silicon does with holding the styro together by itself, however I think the Drylok will help keep things together pretty well. I actually put one thin coat of Drylok on the back side of the BG to cover the pink and in my mind I think the silicon will adhere to that better than the styro.

I plan on using every bit of that 6 tubes on the back. I'm relying on strength in numbers for the background to stick.

Also, the physics of how it will work in my mind relate to the special snow/ice tires used up north in Alaska (instead of studs) it's called "siping" and it's basically a bunch of little cuts in the tread block that increase the number of rubber edges that contact the surface of the ice to give a car traction that it wouldn't otherwise have. When I look at the back of my BG and see all those edges of the boards that will be in contact with the glass and silicon, I reason that it will work using the same principals as the siping. (Look up Blizzak tires for a better idea)

Of course this is all just BS theory in my mind and I'm really just doing it based on blind faith in the internet community that did it before me and had only a FEW horror stories about not using enough silicon and having adhesion failure. I have yet to read anyone using massive amounts of silicon and have adhesion failure.

I think it's a good theory. Because the more surface area the better chance for the silicone can adhere too. Isnt that the reason why sand holds more beneficial bacteria because there's more surface area. I'm just a new though, so most likely I still don't know what I'm talking about lol

Long ago we would just dissolve the styro and leave the shell. We generally incorporated fiberglass mesh into the build to give support. Without the styro it won't float. We just sealed around the edges.